how do I set up the problem?

Question

An object was dropped from the top of a lighthouse. It took 4 seconds for the object to hit the ground. How tall is the lighthouse?

Answer 1

Same concept, just use 32.2 ft/s² for the acceleration of gravity instead of 9.81. Or you can convert meters to feet

Answer 2

The distance an object moves, starting from rest, under a constant acceleration is equal to (1/2)at^2.* Gravitational acceleration changes with height; infinitely far from Earth, the acceleration is zero. Close to the Earth’s surface, the acceleration is a constant 9.81 meters per second per second.

we can assume a = 9.81 meters per second per second.

So, let's take that 4 seconds and solve for the height. We have:

h = (1/2) a t^2 = (1/2) (9.81) (4)^2 = 78.48 meters

The building is 78.48 meters tall!